2627 Plant Tissues & Anatomy of Root, Stem and Leaves

Sclerenchyma

Multiple Choice

Which of the following is not a ground tissue?

• Parenchyma

• Collenchyma

• Sclerenchyma

• Xylem and Phloem

Multiple Choice

What ground tissue is the most abundant?

• Parenchyma

• Collenchyma

• Sclerenchyma

• Xylem and Phloem

Multiple Choice

A young sunflower stem bends significantly during strong winds but returns to its original position without breaking. Which ground tissue most likely contributes to this ability?

• Sclerenchyma, because its cells have heavily lignified walls

• Collenchyma, because its unevenly thickened walls provide flexible support

• Parenchyma, because its cells are specialized for rigid structural support

• Xylem, because its vessels provide flexibility to the stem

VASCULAR TISSUES: XYLEM

• Transport water and dissolved minerals from the roots to all parts of the plant.

• Water conducting cells are elongated and have thick, lignin-rich secondary walls.
  

Tracheids - long, narrow cells that overlap at their tapered end. Waters moves through pits.
Vessel element - short, wide, barrel-shaped, long continuous tubes. End walls are perforated/ absent. Water movement is faster than tracheids.

VASCULAR TISSUES: PHLOEM

• Transports dissolved organic compounds, primarily sugars.
  

Sieve tube element - main conducting cells of phloem, align end-to-end to form sieve tubes. Alive but no nucleus and little cytoplasm.
Companion cell - specialized parenchymal cell adjacent to sieve tube element. Transfers Carbohydrates into and out pf the sieve tube elements. Provides energy and proteins to the conducting cells.

Multiple Choice

What is the main conducting cells of phloem?

• companion cells

• sieve tube elements

• tracheid

• vessel element

Multiple Choice

What complex molecule adds
strength to cell walls?

• Cuticle

• Lignin

• Starch

• Cellulose

Multiple Choice

A young plant is exposed to strong winds for several weeks. Researchers observe that the plant develops thicker stems and increased support in older regions. Which tissue most directly contributes to this structural adaptation?

• Parenchyma, because it stores nutrients for growth

• Collenchyma, because it provides flexible support to growing regions

• Sclerenchyma, because its thick, lignified walls provide rigid support

• Epidermis, because it regulates gas exchange

Multiple Choice

A researcher examines two regions of a plant stem. Region X contains living cells with thin primary cell walls and numerous chloroplasts, while Region Y contains cells with thick, lignified secondary walls and very little cellular content. Which conclusion is most appropriate?

• Region X is primarily involved in photosynthesis, while Region Y provides mechanical support.

• Region X provides rigid support, while Region Y primarily performs photosynthesis.

• Both regions primarily function in long-distance transport of water.

• Both regions consist mainly of dead cells specialized for protection.

​Dermal Tissue

• Covers the plant

• Herbaceous plant contains epidermis - single layer of packed, flat, transparent, parenchyma cells

​Dermal Tissue

• Cuticle - waxy layer that coats the epidermis of the leaves.

• Woody plant contains tough bark

​Dermal Tissue

• cuticle also conserves the water and protects the plant from predators and fungi.

Multiple Choice

A plant growing in a hot, dry environment develops a thicker waxy layer on its leaves. What is the most likely advantage of this modification?

• It increases the rate of water absorption by the roots.

• It reduces water loss from the leaf surface.

• It increases sugar transport through the phloem.

• It allows more carbon dioxide to enter the leaf.

Multiple Choice

A scientist observes that a plant's leaves have damaged guard cells surrounding most of their stomata. Which physiological process would most likely be directly affected?

• Regulation of gas exchange and water loss

• Transport of sugars through the phloem

• Production of lignin in sclerenchyma

• Cell division in the vascular cambium

Multiple Choice

A student applies petroleum jelly to the entire surface of a leaf, covering both the epidermis and stomata. After several hours, the leaf begins to wilt. Which explanation best accounts for the observation?

• The petroleum jelly increases the activity of the stomata.

• The coating interferes with normal gas exchange and disrupts the balance of water movement.

• The epidermal cells immediately stop undergoing mitosis.

• The coating causes the xylem to transport sugars instead of water.

Multiple Choice

Plants that stop growing after they reach their mature is known to have determinate growth. True or False?

• True

• False

Multiple Choice

Which type of growth lengthens the shoot or root tip by adding cells?

• Determinate

• Indeterminate

• Primary

• Secondary

Multiple Choice

Which among the following shows a shoot apical meristem?

Multiple Choice

What type of growth increases the girth of stems and roots in woody plants?

• Primary

• Secondary

• Determinate

• Indeterminate

Multiple Choice

The vascular cambium gives rise to what tissue(s)?

• Xylem and Phloem

• Phloem only

• Xylem only

• None of the above

Multiple Choice

Which of the following best describes a root?

• Roots are the primary site of photosynthesis.

• Roots give rise to new leaves and flowers.

• Roots have a thick cuticle to protect the epidermis.

• Roots absorb water and nutrients.

Multiple Choice

Why are root hairs important to plants?

• Root hairs anchor a plant into the soil.

• Root hairs store starches.

• Root hairs increase the surface area for absorption.

• Root hairs provide habitat for nitrogen-fixing bacteria.

Multiple Choice

What is the layer that covers the apical meristem of a root?

• Root cap

• Zone of elongation

• Zone of cell division

• Zone of maturation

Multiple Choice

Which of the following do lateral roots emerge from?

• Epidermis

• Cortex

• Pericycle

• Endodermis

Multiple Choice

Which of the following is formed when the nutrition of some plants is enhanced by a mutually beneficial interaction between a root and soil bacteria?

• Nodules

• Mycorrhiza

• Haustoria

• Hypha

Multiple Choice

Which example below is the site of primary growth that results in the plant’s increase in height?

• Apical meristems

• Nodes

• Bud Scales

• Lateral meristem

Multiple Choice

Some plants grow by primary and secondary mechanisms. Choose the correct description of a mechanism and its result.

• Primary growth increases the girth of the plant.

• Stems that only experience primary growth are called woody plants.

• Primary and secondary growth are required to produce woody plants.

• Secondary growth, a feature of herbaceous plants, extends the length of the plant.

Multiple Choice

Which of the following correctly describes a feature unique to monocot stems?

• Ground tissue consists mainly of parenchyma cells.

• Vascular bundles are arranged in a ring.

• Vascular tissue is located all in the center.

• Vascular bundles are scattered throughout the stem.

Multiple Choice

Which of these is a stem?

• Carrot

• Pneumatophore

• Ginger

• Spines of cactus

Multiple Choice

Which of the following is the main function of leaves?

• 
  Transport water

• Support the weight of the plant

• Transport sugar

• Absorb sunlight

Multiple Choice

The very top of the leaf has a thin coated waxy surface. What is the name of this leaf part?

• Cuticle

• Stomata

• Spongy mesophyll

• Palisade mesophyll

Multiple Choice

Microscopic openings in the leaf regulate the gas exchange of carbon dioxide and oxygen. They also allow transpiration of the leaf to occur. What is this opening called?

• Cuticle

• Stomata

• Spongy mesophyll

• Palisade mesophyll

Multiple Choice

In which part of the leaf are chloroplasts most abundant?

• Vascular bundle

• Epidermal layer

• Mesophyll

• Guard cells